WASHINGTON – Amid an onslaught of criticism, the Obama administration has dropped plans to ban a popular type of rifle ammunition that can pierce a police officer's protective vest if fired from a handgun, the Bureau of Alcohol, Tobacco, Firearms and Explosives said Tuesday.

More than 80,000 people have commented on the proposal to ban certain types of 5.56 mm, or .223 caliber, ammunition since the agency announced its proposal last month. An ATF spokeswoman, Ginger Colbrun, said the vast majority of comments were critical of the proposal.

Objections also came from 291 members of Congress — majorities of both the House and Senate.

The ATF had proposed banning some types of ammunition used in the popular AR-15-style rifles. The rule change would have affected only "M855 green tip" or "SS109" rounds with certain types of metal core projectiles.

In a letter to ATF Director B. Todd Jones last month, House Judiciary Committee Chairman Bob Goodlatte, R-Va., objected to the plan. On Tuesday, he applauded the reversal, saying he was "pleased that the Obama administration has abandoned its attack on the Second Amendment."

Armor-piercing handgun ammunition has been banned since 1986 as a way to protect police officers under the federal Law Enforcement Officers Protection Act. The rifle bullets considered under the ban were long thought to be considered exempt because they were used for "sporting purposes," such as target shooting.

Colbrun said ATF proposed ending the exemption in part because of the advent of AR-style pistols that can fire the rounds. Such guns did not exist when the armor-piercing ammunition law was passed.

She said the legislation also did not define "sporting purposes," which has led to more than 30 requests for exemptions in recent years.

Without a new framework to determine which armor-piercing ammunition is strictly for sporting purposes, Colbrun said, those exemption requests cannot be processed.